Recently there is a technique for displaying a hierarchical structure of calling relationships in execution of program by representing functions of program execution and calling relationships of methods using a time axis and an axis indicating called functions and methods. In this technique, information about which function and method are calling certain function and method and which function and method are called by the certain function are collected for every calling in program execution, and calling relationship is visualized based on the collected information.
Furthermore, there is a technique for analyzing information about program execution, compressing and abstracting the analyzed information and displaying the compressed and abstracted information as a sequence diagram. In this technique, by compressing redundant parts in the information, and not by directly displaying every calling information, it is possible to display a further simple and readable sequence diagram.